Detective Inspector Paul Speight, of Merseyside Police, said: "Sean Cox remains in hospital in a critical condition at Walton Neurological Centre. Our thoughts are very much with his family who are going through an extremely tough time, and we want to bring anyone responsible to justice.

"We have studied CCTV footage and have spoken to a number of witnesses, and I want to thank the people who have already come forward for their ongoing support.

"We know there were a number of people filming on camera phones before and after the incident, and we are very keen to hear from them and view the footage as it could prove vital to our investigation of this incident."